The present invention relates to a support apparatus for supporting work holders, particularly in applications where a plurality of work holding devices are employed to grip or clamp a panel type work piece at several different locations to stably support the panel either in a fixed position for the performance of a work operation on the panel or to transfer the panel from one work station to another.
An apparatus of this type is typically, but not exclusively, used in automotive related applications to handle panels which are to be subsequently assembled into a vehicle door or vehicle body. These panels typically have lengths and widths of two or more feet and are frequently of irregular shape or formed with irregular openings so that in order to stably and firmly support the panel, it is necessary that the work holders grip the panel at several locations along its peripheral edge or the edges of major openings in the panel. The work holders, which typically take the form of grippers of a general type shown in U.S. Pat. No. 3,635,514 or U.S. Pat. No. 4,449,745, clamps or vacuum cups, are typically mounted on support members or a support frame by means of a ring type clamp which is received on a cylindrical support rod. This arrangement allows the individual work holder to be adjusted longitudinally of the support rod and rotatively about the axis of the support rod and then clamped by the ring clamp in the adjusted position. Because of the irregular shape of panels handled by this particular type of apparatus and the fact that automated production procedures can require extremely precise positioning of the panel relative to tooling employed to operate on the panel, the two degree of freedom adjustment capability of the rod-ring clamp arrangement just described does not always enable all of several work holders to be accurately and independently positioned relative to one another. The present invention is directed to a work holder support apparatus which provides a greatly improved flexibility of adjustment.